Apparatus for covering cores



July 4, 1950 D. D. JONES APPARATUS FOR covERING coREs Filed Sept. 18,

2 Sheeht's-Sheet 1 D. D. JONES APPARATUS FOR COVERING CORES July 4, 195o 2 Sheets-Sheet 2 Filed Sept. 18, 1946 S. .mhwalommmrul WN QN myn/Tof? D. 0.JONE$ ATTORNEY Patented July 4, 1950 UNITED STATES PATENT OFFICE APPARATUS FOR COVERING OORES David D. Jones, Weston, Conn., assignor to Western Electric Company, Incorporated, New York, N. Y a corporation of New York Application September 18, 1946, Serial No. 697,809

(c1. 1raisi 7 Claims. l

This applicationy relates-to apparatus for covering cores, and more particularly to apparatus designed to continuously apply coverings of insulating or jacketing materials over cores, such as filamentary conductors and the like.

In the manufacture of insulated conductors, either bare or covered lamentary conductors are sometimes advanced continuously from supply reels through extruders and elongated continuous vulcanizing tubesv by takeup` capstans positioned at the ends of the vulcanizing tubes. 'Ihe extruders continuously extrude coverings of vulcanizable materials over the conductors as they are advanced from the supply reels therethrough. Since the vulcanizing tubes are relatively long, the portions of the conductors between the extruder and the takeup capstan sag considerably, if the supply reels from which the conductors are drawn are not balanced, or if the conductors are unevenly distributed on the supply reels, the ccnductors are advanced through the extruders with nonuniforrn tensions on diiferentportions thereof passing through the extruders. Since. the extruders feed material at a substantially constantv rate of speed, variations in the tension of the conductors cause variationsv in thethickness of the coverings formed by the extruders. Placing freely rotatable sheaves betweenv the supply spools and the extruders tendsV to,v smooth out the rate of feed from unbalancedsupply reelsr but acts only as a dampener on `the variations intensionson the conductors. In the past,` there have been norsatisfactory means for feeding conductors` through the extruders under uniform tensions,

An object of the invention is to provide new and improvedapparatus for covering cores.

A further objectof the invention is to provide new and improved *machinesl for formingv uniform coverings of insulating or jacketing materials on cores, such as lamentary conductors and the,

like.

An apparatus illustrative l ofthe; invention, includes, in the order named,a supply reel, a positively driven supply capstan, a continuous extruder, an elongated vulcanizing; tube, a takeup capstan, and a slipping, drive. for rotating. the takeup capstan and a takeup reel. The supply capstan and a stock screwof the extruder are positively driven through a;A common drive, and hence, have constantr relative speeds. A .conductor Withdrawn from the supply reel is wrapped around the supply capstan, which rotatesto positively advance the conductcrfrom the supply reel atthe rate of peripheral speedY of the capstan'.V The takeup capstanis driven by theuk slipping.

driverwhich maintains a constant torque on the takeup capstan, so that the portion of the conduotor between the takeup capstan and the supply capstan is maintained under a uniform tension as the takeup capstan advances the conductor through the extruder and the Vulcanizing tube. Since the supply capstan advances the conductor from the takeup reel positively and the takeup capstan maintains a constant tension on the conductor, any nonuniformity in tension on the conductor that might result from uneven distribution of the conductor on the supply reel` or from unbalance in the supply reel Ais eliminated.

A complete understanding of the invention may beobtainedV from the following detailed description of an insulating machine forming a specific embodiment thereof, when read in conjunction with the appended drawings, in which:

Fig. 1 is a fragmentary, iront elevation of an insulating machine forming one embodiment of the invention;

Fig. 2 is an enlarged, fragmentary, top plan View of the machine with a portion thereof shown in section, and

Fig. 3 is an enlarged, fragmentary, partially sectional View of a portion of the machine.

Referring now in detail to the drawings, a con-1 ductor I e; (Fig. l), which may be bare or covered, isadvanced from a supply reel I I mounted rotatably, cna supply stand I2 by a supply capstan I3. The supply capstan I3 is driven through a shaft I4, worm gearing I5, a shaft I6, a variable gear box 20, a shaft 2|, a pulley 22, a belt 23, a pulley 2li-and a shaft 25 driven by an electric motor 26. The conductor I0 is Wrapped at least once completely around the capstan I3, and a presser belt 3,0 mounted on freely rotatable pulleys 3I-3I presses the conductor IU tightly against the capstany I 3 sothat slippage between the conductor Iland the capstan I3 is prevented. Hence, the conductor Ill is advanced by the supply capstan {Birollithe supply reel II at a constant speed regardlesslof unbalance of the supply reel II or uneven distribution of the conductor IIJ on the supply reel II.,` if either or both of these conditions are present.

Theconductor I0 is pulled through an extruder 32 having a stock screw 33, which forces a vulcanizable insulating or jacketing material 3d through apassage 35 in a cylinder 36 of the extruder 32 at a constant rate of now for a given rate of rotation of the stock screw 33. A forming die 4 04 of` a predetermined size serves to form i the, vulcanizable material 34 into a covering 4I around the conductor I0. The stock screw 33 is driven by a shaft 42 driven by the shaft 25 through worm gearing 43. Since the rate of rotation of the stock screw is constant with respect to the rate of rotation of the supply capstan I3, the rate of speed at which the conductor Ill is advanced by the supply capstan is constant with respect to the rate of delivery of vulcanizable material by the stock screw 33 for any particular setting of the variable gear box 20.

The covered conductor I is advanced from the extruder 32 into and through an elongated ,vulcanizing tube 50 positioned in tandem with the extruder. A vulcanizing medium, such as steam, or the like, is introduced under pressure into the vulcanizing tube u to vulcanize the covering 4I.

The covered conductor passes into` a suitable,

water seal 5I, land then is passed around a takeup captan 52 and is wound upon a takeup reel 53. A presser belt 54 mounted on freely rotatable pulleys 55-55 presses the conductor tightly against the takeupcapstan 52 so that there is no slippage between the conductor and the takeup capstan. f

The takeup capstan 52 is mounted on a shaft 6l) of a magnetic clutch motor drive Si of 'a wellknown type. The motor drive SI includes an induction motor 52 having a shaft 53, which is rotated by the motor 52, and a magnetic clutch 59. A drum 64 composed of magnetic material is fastened rigidly to the shaft 63 and is rotated therewith. A spider 65 having poles 66 and 61 is fastened rigidly to the shaft 60. rAny annular coil 'Ill fastened rigidly to the spider 55 is connected electrically by the conductors II and 'I2 to slip rings`13 and 14, respectively, to which slip rings electricv current is supplied, whereby the electric current ows through the annular coil 'I0 to cause magnetization of the poles B6 and 61, which are spaced from the drum 64 `by a slight air gap l5. The magnetization of the poles 56 and 67 magnetizes the portion ofthe drum 34 adjacent thereto, and, as the drum 64 is rotated by the motor 62, the drum 64 draws the spider 65 therewith with some slipping therebetween, whereby the shaft 6I) is rotated. The motor 62 will exert a constant predetermined torque upon the shaft 63, which torque is transmitted by the shaft 60 to the takeup capstan 52, but permits slipping between the drum 64 and the spider 65. The takeup capstan 52 exertsa constant predetermined pull upon the covered conductor, which pull is sufficient t'o pull the conductor I0 from the supply capstan `I3 atthe same rate of speed at which the capstan i3 advances the conductor. Hence, the capstans 52 and I3 advance the conductor It] at a constant, predetermined rate of speed and. maintain the conductor I0 under a constant, predetermined tension so that the vulcanizable material 344 is formed uniformly around the conductor.v An electronic control 'I9 of a'wellknown type may be adjusted to vary the'torque applied by the drive GI to the takeup capstan 52. Thus, the tension imparted by the takeup capstan 52 may be varied for covered conductors having different weights per unit of length than that of the covered conductor I0.

In the operation of the apparatus described hereinabove, the conductor I is passed around and advanced by the supply capstan I3 at a constant rateofspeedfor any particular settings of the motor 26 and the variable gear box 20 so that the supply capstan I3 acts as a measuring capstan. The takeup capstan 52 is rotated by the drive `Il and` transmits a predeterminedcanizing tube 50 and the seal 5I as fast as the supply capstan I3 will permit the conductor I0 to be advanced, which will be at a constant rate of speed regardless of any unbalance of the reel II or nonuniformity in distribution of the conductor I0 thereon.l

The stock screw 33 is driven in synchronization with the supply capstan I3, which regulates the rate of speed in which the conductor I0 may be drawn through the extruder 32 by the takeup capstan 52 so that the Vulcanizable material 34 is extruded by the extruder 32 at a rate of speed, which is constant relative to the rate of speed of the conductor. -Since the rate of flow of the vulcanizable material from the extruder 32 and the rate of speed of theconductor I0 and the tension thereof are constant, the covering 4I formed around the conductor I3 is uniform and is not affected by irregularities in the feed of the portion of the conductor I between the supply reel I I and the supply capstan I3.

The extruder 32 is suitable for extruding many types of plasticmaterials over conductors. For example, it may be used to extrude thermoplastic compounds aswell as vulcanizable compounds. If the estruder is used to extrude thermoplastic materials,` water rather than a vulcanizing medium may be inserted into the vulcanizing tube 50. 0r, an elongated cooling trough (not shown) lled with water may be'substituted for the vulcanizing tube when thermoplastic material is extruded by theextruder.

Other types of slipping drives than the drive 6I maybe used to drive the takeup capstan 52. For example, either a slipping mechanical clutch or a torque motor might be used in place of the drive 6I.

What is-claimed is:

l. Apparatus for covering cores, which comprises means for supporting a continuous core, an extruder for continuously forming plastic material around such'a core, means positioned between the core-supporting means and the continuous extruder for positively advancing the continuous core fromthe core-supporting means at a constant rate of `vspeed, a second core-advancing means for advancing the core through the extruder from the first-mentioned core-advancing means,and a slipping drive for driving the second core-advancing means.

2. Apparatus for covering cores, which comprises means for supportinga continuous core, an extruder for continuously forming plastic material around such a core, means positioned between `the core-'supporting means and the continuous extrud'er for positively advancing the continuous core from the core supporting means at a constant rate of speed, a second core-advancing means for advancing the core through the eX- truder from the first-mentioned core-advancing means, and means including a magnetic clutch for driving the' second core-advancing means.

f .3. Apparatus 'for covering cores, which comprises a supply reel, means for Imounting the supply reel-rotatably7 sothat a lament wound on the;

supply reel may be advanced therefrom, a supply capstan for advancing the filament from the supply reel at a constant rate of speed, a takeup reel, a takeup capstan positioned between the takeup reel and the supply capstan, means including a slipping drive for -applying a constant torque to the takeup capstan to place a constant tension on the portion of the lament between the supply capstan and the takeup capstan and to advance that portion of the filament at said constant rate of speed, and an extruder positioned between the supply capstan and the takeup capstan for eX- truding plastic material over the iilament at a constant rate.

4. Apparatus for covering cores, which comprises a supply reel, means for mounting the supply reel rotatably so that a filament wound on the supply reel may be withdrawn therefrom, a supply capstan for withdrawing the filament from the supply reel at a constant rate of speed, a takeup reel, a takeup capstan positioned between the takeup reel and the supply capstan, adjustable means including a, slipping drive for applying a predetermined torque to the takeup capstan to place a constant tension on the portion of the ilament between the supply capstan and the takeup capstan and to advance that portion of the lament at said constant rate of speed, means for adjusting said torque-applying means to vary said predetermined torque, and an extruder positioned between the supply capstan and the takeup capstan for extruding plastic material over the lament ata constant rate.

5. Apparatus for covering cores, which comprises a supply reel, means for rotatably supporting the supply reel to permit a core wound on the supply reel to be unwound therefrom, an extruder for continuously forming a covering over the core, means including a slipping drive for applying a predetermined pull to the covered core to advance the core through the extruder, and means positioned between the supply reel and the eXtruder for limiting the rate of speed at which the pullapplying means may pull the core through the extruder.

6. Apparatus for covering cores, which comprises a supply reel, means for rotatably supporting the supply reel to permit a conductor wound on the supply reel to be unwound therefrom, an extruder including a stock screw for continuously forming a covering over the conductor, means for rotating the stock screw at a predetermined rate of speed, means for applying a predetermined pull to the covered conductor to advance the conductor through the extruder, conductor-advancing means positioned between the supply reel and the extruder for positively advancing the conductor, and positive drive means for driving the conductor-advancing means in synchronization with the screw-rotating means.

7. Apparatus for covering cores, which comprises a supply reel, means for mounting the supply reel rotatably so that a, conductor wound on the supply reel may be advanced therefrom, a supply capstan for advancing the conductor from the supply reel, means for pressing the conductor against the supply capstan to prevent slipping therebetween, means for positively driving the supply capstan at a predetermined peripheral rate of speed, a takeup reel, a takeup capstan positioned between the takeup reel and the supply capstan, means including a magnetic clutch for applying a constant torque to the takeup capstan to place a constant tension on the portion of the conductor between the supply capstan and the takeup capstan and to advance that portion of the conductor at the same rate of speed as that at which the supply capstan advances the conductor, a continuous extruder positioned between the supply capstan and the takeup capstan, said extruder including a stock screw for forcing plastic material over the conductor, and means for driving the stock screw in synchronization with the supply capstan-driving means.

DAVID D. JONES.

REFEREN CES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,069,087 Forstrom et al Jan. 26, 1937 2,137,887 Abbott Nov. 22, 1938 

